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7.2.7. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines

Before you install a cluster on IBM Power infrastructure that you provision, you must create RHCOS machines for it to use. Follow either the steps to use an ISO image or network PXE booting to create the machines.

7.2.7.1. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines using an ISO image

Before you install a cluster on IBM Power infrastructure that you provision, you must create RHCOS machines for it to use. You can use an ISO image to create the machines.

Prerequisites

  • Obtain the Ignition config files for your cluster.
  • Have access to an HTTP server that you can access from your computer and that the machines that you create can access.

Procedure

  1. Upload the control plane, compute, and bootstrap Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.

    重要

    If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

  2. Obtain the RHCOS images that are required for your preferred method of installing operating system instances from the RHCOS image mirror page.

    重要

    The RHCOS images might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Use the image versions that match your OpenShift Container Platform version if they are available. Only use ISO images for this procedure. RHCOS qcow2 images are not supported for bare metal installs.

    You must download the ISO file and the RAW disk file. Those file names resemble the following examples:

    • ISO: rhcos-<version>-installer.<architecture>.iso
    • Compressed metal RAW: rhcos-<version>-metal.<architecture>.raw.gz
  3. Upload either the RAW RHCOS image file to your HTTP server and note its URL.

    重要

    If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

  4. Use the ISO to start the RHCOS installation. Use one of the following installation options:

    • Burn the ISO image to a disk and boot it directly.
    • Use ISO redirection via a LOM interface.
  5. After the instance boots, press the TAB or E key to edit the kernel command line.
  6. Add the parameters to the kernel command line:

    coreos.inst=yes
    coreos.inst.install_dev=sda 1
    coreos.inst.image_url=<image_URL> 2
    coreos.inst.ignition_url=http://example.com/config.ign 3
    ip=<dhcp or static IP address> 4 5
    bond=<bonded_interface> 6
    1
    Specify the block device of the system to install to.
    2
    Specify the URL of the RAW image that you uploaded to your server.
    3
    Specify the URL of the Ignition config file for this machine type.
    4
    Set ip=dhcp or set an individual static IP address (ip=) and DNS server (nameserver=) on each node. See Configure advanced networking for details.
    5
    If you use multiple network interfaces or DNS servers, see Configure advanced networking for details on how to configure them.
    6
    Optionally, you can bond multiple network interfaces to a single interface using the bond= option, as described in Configure advanced networking.
  7. Press Enter to complete the installation. After RHCOS installs, the system reboots. After the system reboots, it applies the Ignition config file that you specified.
  8. Continue to create the machines for your cluster.

    重要

    You must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, which is the default, also create at least two compute machines before you install the cluster.